C++ Stack Library - operator== Function


Description

The C++ function std::stack::operator== tests whether two stacks are equal or not.

Declaration

Following is the declaration for std::stack::operator== function form std::stack header.

C++98

template <class T, class Container>
bool operator== (const stack<T,Container>& stack1,
                 const stack<T,Container>& stack2);

Parameters

  • stack1 − First stack.

  • stack2 − Second stack.

Return value

Returns true if both stacks are equal otherwise false.

Exceptions

This function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::stack::operator== function.

#include <iostream>
#include <stack>

using namespace std;

int main(void) {
   stack<int> s1;
   stack<int> s2;

   for (int i = 0; i < 5; ++i) {
      s1.push(i + 1);
      s2.push(i + 1);
   }

   if (s1 == s2)
      cout << "Both stacks are equal." << endl;

   s1.push(6);

   if (!(s1 == s2))
      cout << "Both stacks are not equal." << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

Both stacks are equal.
Both stacks are not equal.
stack.htm
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